Pages

Wednesday, 4 June 2014

Cosmos - The World Set Free

The
world is a beautiful place, full of awe-inspiring sights and teeming
with millions of lifeforms. Yet the world is a fragile place, too.
Life has evolved within a very delicate balance of elements in the
atmosphere. Alter that balance just a little and things can change
drastically. We have known about global warming for quite some time
now, but we have been slow to do anything about it. Indeed, there are
many who deny its implications or even its entire existence. They
dismiss the overwhelming evidence simply because it doesn’t fit
their world-view. Climate change is a gradual process, and even at
its current accelerated rate, it’s not something noticeable to the
naked eye from day to day or year to year. And because we can’t see
it, it’s hard to accept. But simply because something is hard to
see doesn’t make it untrue.

A
few episodes ago, in “The Lost Worlds of Planet Earth”, Cosmos explored
long-term climate change, looking at the many different kinds of
worlds the Earth has been. Most of that climate change has been
completely natural. Climate does change on its own over thousands and
millions of years, and even without human influence, it would
continue to change. That episode also touched on modern climate
change, drawing attention to the fact that we are releasing carbon
into the atmosphere through the burning of fossil fuel at an
incredible rate, and it was the release of carbon from the
Carboniferous period that ended the Permian and drastically altered
the world’s climate.

In
the most recent episode, “The World Set Free”, Cosmos
returns to the topic of climate
change and this time looks closely at human-created climate change
and the phenomenon of global warming that we must deal with today.
There is absolutely no reason any of this episode should be
controversial, and yet there are many that will make it so. Still,
this is knowledge that we must absorb and Cosmos,
in its usual way, presents it clearly and accessibly, and in an
entertaining fashion.

The
episode begins with a look at Venus and what we think it might have
been like in the early years of the solar system, a couple billion
years ago. Venus had oceans back then and may well have been a
paradise. But along the way, Venus lost its oceans and fell victim to
a runaway greenhouse effect. Now it’s one of the hottest places in
the solar system and this isn’t because it’s closer to the sun
than Earth. It’s because of the carbon dioxide in its atmosphere
which traps the heat of the sun. Venus and Earth started with roughly
the same amount of carbon. However, without its oceans to reabsorb
it, volcanic eruptions on Venus left that carbon almost entirely in
the atmosphere, whereas on Earth, there has always been a delicate
cycle of carbon release and reabsorption.

There’s
actually not a lot of carbon dioxide in the atmosphere, historically
less than 300 parts per million (although that has risen alarmingly
now). It doesn’t take much to make a change. No
carbon dioxide at all in the atmosphere
would leave the Earth as a completely frozen ball, and not even twice
as much would make the world uncomfortably hot and cause major
problems—although nowhere near the level of Venus.

Neil
deGrasse Tyson is quick to stress that Venus’s runaway greenhouse
effect was entirely natural. Nature is quite capable of destroying
the world on its own without human intervention. So, if nature is
capable of such devastation (and we’ve seen it here on Earth before
with the various mass extinctions, ice ages, and so on that have
occurred over the last few hundred million years), how can we be sure
that the climate change we are experiencing now is not also natural
and, in fact, human-caused? The episode proceeds to take a look at
the answers to this question, starting with an examination of
volcanic eruptions.

Volcanoes
do, indeed, release large amounts of carbon dioxide into the
atmosphere—on the order of five hundred million tons annually. As
Tyson says, “Sounds like a lot, right? But that’s not even two
percent of the thirty billion
tons of CO2
that our civilization is cranking out every year.” More than that,
volcanic CO2
has a different signature (atomic weight) to that of CO2
from the burning of fossil fuels, and the measurements taken of CO2
in the atmosphere show it to be the fossil fuel burning kind, not the
volcanic kind.

Later
in the episode, Tyson also examines another argument for natural
global warming: that the sun is responsible. However, we have been
monitoring the sun for decades and its output has remained unchanged.
More so, global warming has been more pronounced at night and in the
winter, which is the exact opposite of what would be expected from
increased solar output, but exactly what is expected of increased CO2
in the atmosphere.

One
of the things I continue to like so much about Cosmos
is the way it does more than just explain things in words. Tyson’s
narration is great, and as an auditory learner myself, I appreciate
it greatly. However, the visual representations, animation, and
computer effects go a long way to making the material easily
accessible to the average viewer. One of the best examples of this
can be seen in this episode and it doesn’t take any fancy computer
effects to achieve.

One
of the biggest misunderstandings people have about global warming is
the difference between climate and weather. Predicting the weather is
pretty hit and miss at times, and long-term forecasts are pretty much
useless. Given that, how can scientists be so sure about climate
changes? How do they know that, next year, everything won’t
suddenly start cooling down? In fact, here in Toronto where I live
(and in much of southern Ontario and the northeastern United States),
we just had one of the coldest and snowiest winters I can recall
having in the past twenty years or more. So much for global warming,
right? I’ve actually seen people say that, completely ignoring the
fact that such winters used to be much more common and are now
comparatively rare. Tyson very neatly unravels the confusion between
climate and weather with nothing more than a walk on the beach with
his dog. The dog wanders all over the place, but still maintains an
overall direction of travel because he’s on a leash held by Tyson.
Tyson himself walks in a straight line. I really can’t think of a
better way to show the difference than this. The dog represents the
randomness of weather, while Tyson represents the predictability of
climate. The weather can change drastically from day to day, but over
the long-term, climate is very predictable.

The
episode also clears up some other misconceptions about global
warming, noting that the majority of the warming is in the oceans.
The warming oceans are causing the polar ice caps to recede. Ice
reflects heat, but liquid water traps it. As the ice melts, less heat
is reflected, meaning the oceans heat up even more. It creates a
positive feedback loop (and positive
here is not a synonym for good).

But
“The World Set Free” is not all doom and gloom. Indeed, as the
title implies, there’s much to hope for. Venus’s fate was
unstoppable, but Earth is not in the same situation as Venus, and
it’s still possible to stop global warming on Earth and maybe even
reverse it. The episode spends considerable time looking at the
options open to us, in particular on solar power. I was actually
rather surprised to learn that the first solar generator was invented
in the 19th century by Augustin Mouchot (whom I hadn’t heard of
before), but he lost his funding to coal. The episode then tells us
of Frank Shuman’s attempts to place solar generators throughout the
Sahara Desert just before the outbreak of the First World War. In
typical Cosmos manner,
the episode uses history to teach us about the things we could be
doing now.

Touching
on wind power as well as solar, the episode also shows us how,
ultimately, everything goes back to the sun. Wind is reliant on the
sun to form, and so even are the fossil fuels we burn. Without the
sun to provide the original energy, those fossil fuels would never
form in the first place. Even if, somehow, we are wrong about global
warming, doesn’t it make more sense to go to the source for our
energy? Isn’t it more efficient? Every day, more energy than we
could possibly need bombards this planet from the sun. All we need to
do is collect it.

But
first, we need to take our fingers out of our ears and stop
attempting to drown out the things we don’t want to hear. Science
is about evidence, not opinion, and the evidence points in only one
direction. Changing our ways won’t be easy; it’ll be pretty damn
hard, but humanity has often been at its most inventive when faced
with the greatest difficulty. To illustrate this, “The World Set
Free” ends with a look at the race to the moon, which came about
because of the nuclear arms race. It includes John F. Kennedy’s
famous words about why America should go to the moon: “Not because
[it is] easy, but because [it is] hard.” Cosmos has
done a great job presenting the situation for us; now it’s past
time to take what we’ve learnt and do something with it.